Palaeoclimatic Influences and the Development of Savanna in Southern Venezuela

Isolated tracts of savanna in the humid environment of southern Venezuela are described. Their distribution is not related to peculiarly adverse soil conditions; nor do the savannas seem to have been formed solely as a result of slash and burn agriculture or direct forest burning. Nevertheless, the savannas are contemporarily fire maintained. In view of these conditions and also of the floristic affinity among tropical American savannas, it is suggested that the savanna islands in southern Venezuela are relics of more widespread savanna which existed under previously drier conditions; the islands have survived locally through burning, in spite of a later tendency to increasing rainfall and general reforestation. Similar relict savannas also exist elsewhere within the main body of the Amazon forest. In currently drier areas such as the llanos and campos cerrados the situation is less clear, but some relict savanna may also exist in places where pyrogenic savanna has been postulated.